1. Field of the Invention
The present invention relates to a food additive comprising water-soluble hemicellulose, more particularly, hemicellulose derived from oil seeds and cereals, and to food containing such an additive.
2. Description of the Related Art
In the preparation of acid protein foods, to prevent an agglomeration and precipitation of protein, in general, a thickener such as himethoxyl pectin (HM pectin), sodium carboxycellulose, or alginic acid propylene glycole ester is utilized. Such a thickener, however, can not completely prevent an agglomeration and precipitation of protein. A phenomenon such as phase separation or precipitation can be prevented by increasing an amount of thickener, but this gives a "heavy" taste and is not popular. Therefore, several attempts to prevent a phase separation and precipitation at low viscosity have been made, but these attempts have not been successful.
Preferably food such as meat and fish jelly products are hard to masticate, and such a property is obtained by increasing the gel strength in the food. This gel strength is achieved, for example, by a network structure obtained by dissolving actomyosin of protein in a solution of salt, and thereafter, heating and denaturating same. To increase the gel strength, polysaccharides such as starch or pullulan are added, but currently, even in meat and fish jelly products such as ham, sausage, and boiled fish paste, there is a demand for softer products. Accordingly, an attempt to lower the gel strength by adding calcium ion or denaturating protein in part was made, but a pleasant feeling when biting into the food has not been obtained yet. Particularly, in meat and fish jelly products, a palatable product having an uneven texture is desired, but such a product has not been developed as yet.
Further, in bakery products such as biscuits, crackers, and sponge cake, a large quantity of fat, margarine and/or emulsifying agent is added to the raw material to improve the palatability thereof. Currently, however, those having a lower fat content are preferred, for their low calorific value, and the use of a large quantity of fat has a defect in that the taste of these products becomes unpleasant. Accordingly, in the preparation of bakery products, gum is added instead of fat or an emulsifying agent. Nevertheless, there is a problem in that the gum itself is expensive and the palatability is not sufficient. Also, even in bakery products, softer products are desired. Further, improvements in storage techniques have enabled the shelf-life of a food to be prolonged. Therefore, during the storage, preferably there is little reduction the palatability of the food.
Also, a nonionic surfactant such as sugar esters, polyglycerine ester, monoglycerides, etc., is utilized as a foaming agent, and it is known that albumen and its decomposition product has a foaming ability. For example, the albumen is utilized in the preparation of meringue. Nevertheless, the foaming agents utilized for food at present are easily affected by pH and temperature changes, and have a poor foaming ability of a lack of stability of the foam itself, and therefore, are not widely used for various purpose. A technique of adding cyclodextrin as an adjuvant, to improve the foaming ability of the albumen, has been developed, but the foaming ability and foam stability are still not sufficient for some specific applications.